Screening method for blood glucose



1951 E. HEFTMANN SCREENING METHOD FOR BLOOD GLUCOSE Filed Feb. 4, 1948 iNVENTOR Patented Feb. 13, 1 951 UNITED STATES PATENT OFFICE SCREENING METHOD FOR BLOOD GLUCOSE I Erich Heftmann, Boston, Mass.

Application February 4, 1948, Serial No. 6,155

(Granted under the act of March 3, 1883, as amended April 30, 1928;370 0. G. 757) Claims.

ratus for checking or determining the sugar content of a blood sample.

Inchecking or determining the sugar content of a blood sample it is not necessary in ordinary circumstances to determine the exact quantity of sugar present. For the practising physicianit normally is necessary merely to discover whether or not the sugar content lies within tolerable limits. The ordinary physician has neither the skill nor the facilities for makin a blood sugar determination employing the usual and known methods of sugar analysis.

It is an object of this invention to afford a simple method for making a quick check of the blood sugar content and to provide compact apparatus for conducting the test. g

It is a further object to provide a method which will require no special laboratory skill or technique.

It is still another object to provide suitable reagents in a handy tablet form, thus eliminating the necessity for careful measurement by the person conducting the test or making the analysis.

In describing the invention, reference will be made to the accompanyin drawing which illustrates the preferred form of the apparatus to be employed in carrying out the process, and in which I Fig. 1 is a front elevation of a kit containing the testing apparatus; I

Fig. 2 is a side elevation of the kit of Fig. 1; and

Fig. 3 is a cross-sectional view of a special test tube making up a part of the kit shown in Fig. 1.

Referring to Fig. .1 of the drawing, in which similar reference characters designate corresponding parts, I is a carrying case which permits a practising physician to make tests while on call. The kit is provided with a graduated test tube 2, shown in detailed section in Fig. 3. The test tube is made of a heat-resistant glass or other suitable material. The lower portion of the tube is of more or less conventional design. At its upper end, however, it is provided with a flared mouth 3, which has an annular depression or lip 4. A pipette 5 provides a means for measuring liquids used in the test or analysis. At 8 is shown a stirrin rod equipped with a scoop or ladle l. A box 8 contains a supply of reagents used in conducting the test. The test tube 2 is mounted in a holder 9, provided with an opening H) for the insertion of solid fuel tablets which are burned to heat the reagents during the test.

In carrying out the test or analysis, reagents in predetermined quantities are made up into tablets for convenient use. The tablets used have the following compositions:

Tablet I Mg. ZnSOsHI-IzO 10 NaCl Talc, suilicient to act as binder. Mineral oil, as lubricant.

Tablet II Mg. KI NaHCOa 10 Tablet III Mg. K2[Fe(CN)e] recrystallized 1.28 NazCOs anhydrous 6.5 Starch (soluble) 1 NaCl l 92 Tablet IV Mg. Tartaric acid 80 ZIlSO4.7H2O 20 Starch, as binder.

The heating tablets are composed of 0.16 mg. of hexamethylenetetramine. Other combustible fuel tablets may be employed for heating the reaction mixture.

In conducting an analysis employing the method and apparatus of this invention, the following procedure is carried out.

The test tube 2 is filled to the 5 ml. mark with Water. An 0.1 m1. sample of blood is added to the water, care being taken that the entire quantity of the blood sample is added. The blood may be measured in a capillary pipette and the pipette rinsed in the water in the test tube. Thereafter one Tablet I and one Tablet II are added to the test tube, which is then heated by igniting two heating tablets in the space In of the holder 9. The blood proteins are coagulated and form a scum which floats on top of the liquid. As the solution boils, the cake of protein is forced to the top by the steam and may be readily reper 100 ml. of glucose.

moved with the scoop or ladle carried by the stirrer 6. The flared mouth of the test tube prevents loss of liquid or reagent by boiling over, and the annular lip or depression catches the protein cake and prevents its return to the solution.

After the removal of the protein another heating tablet is ignited and one Tablet III is added to the solution. When the heating tablet is consumed the test tube is cooled by immersion in cold water. Thereupon one Tablet IV is added to the solution. The solution will then appear blue if free iodine is present, :or will remain substantially colorless if there is no free iodine.

The blood proteins are coagulated by the zinchydroxide formed by the reaction of the zinc sulphate of Tablet I and the sodium bicarbonate of Tablet II. During the subsequent heating in the presence of Tablet III the glucose present in the blood reacts with the KaEFeKCNh]. In the hot solution, alkaline due to the sodium carbonate, glucose reduces K2[Fe(CN)sl to The amount of potassium ferricyanid'ei-n Tablet III is so adjusted that it will be completely reduced by the glucose present in 0.1 m1. of blood when the glucose concentration is 180 mg. per 100ml. :of blood. Cooling and the addition -'of the tartaric acid of Tablet IV interrupts the -reaction. "If the glucose ccncen-tration'is less than 170 mg. per 100 m1. there will be some 'unreacted potassium ferricy'anide left which will react with the KI in Tablet I releasing iodine. In the presence of the zinc sulphate of Tablets I and 'IV, the. released iodine produces a blue color by "rection with the starch of Tablets III andIV.

This procedure provides a quick method for classifying blood samples as containing above 180mg. per 100 ml.fo'f glucose, or below 1'70 mg. This is accomplished by the fixing of the quantities of the reagents and the heating periods.

It "is obvious that by adjusting the quantities of the reagents, and the size of the heating tabletsjthat any selected range of concentrations-of glucose may readily be determined. Thus tablets designed to check the blood sugar concentration between the limit 80 mg. to '70 mg. per 100 may be useful in the emergency diagnosis of hypogiycemla (abnormally low blood sugar content to 0.53 mg. The other tablets remain the same.

Having described the invention, what is claimed is:

1. A method for the determination of the blood sugar concentration of a sample of blood, which comprises making an aqueous solution of a predetermined quantity of blood in a predetermined quantity of water, coagulating the protein of the blood while heating the solution and .then removing the precipitate, adding a predetermined quantity of potassium *ferricyamde, starch and potassium iodide in the presence of an alkaline .It is also apparent that equivalent :reagents,

, method and apparatus in applyingthe underlying principles of-my'invention, and t'he'inventor is not to be limited to the form shown-Or described.

reagent, heating the solution for a predetermined time, then cooling while adding an acid reagent to check the reaction.

A method for checking to determine the blood sugar concentration in a blood sample which comprises adding 1 ml. of blood to 5 m1. of water, heating the solution for a predetermined period in the presence of 10 mg. of ZnSOn'YI-IZO; mg. of iNam; mg. of KI and 10 mg. of NaH'COa, to precipitate .the protein content of the blood and preheat the solution, removing the precipitate, continue heating the solution for a predetermined time in the presence of 1528 mg. of KzFFflCN-lo], 5625 mg. of NazG'Gs, 1;0 mg. of starchan-d 92 mg. of Nam, then cooling the solution 'w-hil'e adding '80 of tartaric -acidj'20 mg. of ZRCOiHEHzO and starch. V

3. An apparatus for conducting chemical reactions which comprises an open container provided with an outwardly flaring iun'nel like extension at its mouth said extension joining the main body=of the container at the exterior thereof and b'elow the upper edge of the mouth to Iorm a-gutter l ike depression around the mouth.

4. method for analyzing the sugar content of a sam le of blood which comprises heating a 5 m'l.aqueoussolutioncontaining 1 ml. of blood, coagulating the protein content of the blood by adding zinc sulphate and sodiumficarbonate to the solution, removing "the coagulated protein, adding and 1.25 mg. of .KaifFetCNds] and starch while continuing theheat'ing, then cooling and adding tartaric acid.

5. .A method as set forth in claim 3, in which .the amountof potassiumlerricyanide is 0553 mg.

REFERENCES prrsn "The following references are or record in the file of this patent: a a a UNITED srnrns mums Number f Name Date 7 stag-33 Stoddard Apr. .14, .1896 735,745 Mar'getts Jiny 26, 1904 938,278 Schultze Oct. 26,j 1'909 2,076,903 Levitt Apr. 13, 1937 zoirnnn REFERENCES ricyanide Method; Industrial and Engineering Chemistry, Analytica -Ed vol. 15,No. :4, April 

1. A METHOD FOR THE DETERMINATION OF THE BLOOD SUGAR CONCENTRATION OF A SAMPLE OF BLOOD, WHICH COMPRISES MAKING AN AQUEOUS SOLUTION OF A PREDETERMINED QUANTITY OF BLOOD IN A PREDETERMINED QUANTITY OF WATER, COAGULATING THE PROTEIN OF THE BLOOD WHILE HEATING THE SOLUTION AND THEN REMOVING THE PRECIPITATE, ADDING A PREDETERMINED QUANTITY OF POTASSIUM FERRICYANIDE, STARCH AND POTASSIUM IODIDE IN THE PRESENCE OF AN ALKALINE REAGENT, HEATING THE SOLUTION FOR A PREDETERMINED TIME, THEN COOLING WHILE ADDING AN ACID REAGENT TO CHECK THE REACTION. 